1. Field of the Invention
This invention relates to a magnetic disk cartridge loading-and-unloading device, and more particularly to a magnetic disk cartridge loading-and-unloading device which loads a magnetic disk cartridge in a recording and reproducing system (In this specification, the term "recording and reproducing system" should be broadly interpreted to include a system for recording only and a system for reproduction only.) and unloads the magnetic disk cartridge from the recording and reproducing system after the cartridge is subjected to a predetermined process in the system.
2. Description of the Prior Art
There have heretofore been provided floppy disks consisting of a flexible base of polyester sheet or the like on each side of which is formed a magnetic layer on which information is magnetically recorded by means of a magnetic head while the disk is rotated at high speed. Because they are easy to handle and are low in cost, such floppy disks are widely used as recording media for computers. These advantages of floppy disks and the fact that they can be reused, which is not possible with silver-halide photographic film, have led to such floppy disks being provided in a smaller form as the image recording media in electric still cameras. For such cameras, the disk is used via a magnetic disk cartridge consisting of a hard casing, within which is rotatably housed the disk.
During production of such magnetic disk cartridges, completed cartridges are generally loaded in a recording and reproducing system in order to check their magnetic layers. In the case of cartridges for specified use, the cartridges are often subjected to a predetermined copying process such as initialization. In such cases, it is preferred that the cartridge be taken out from the recording and reproducing system as soon as the predetermined process is completed and another cartridge be loaded in the system as soon as the preceding cartridge is unloaded, thereby improving the operating efficiency of the recording and reproducing system.
There have been provided various automatic magnetic disk cartridge loading-and-unloading devices for this purpose. Many of the conventional devices essentially comprise, as shown in FIG. 3, a movable member 111 which is movable to a cartridge supply position, a recording and reproducing system and a cartridge discharge position, and a cartridge holding means 110 mounted on the movable member 111. After the cartridge holding means 110 grasps a magnetic disk cartridge 113 at the cartridge supply position, which may be constituted as a supply conveyor 112, the movable member 111 is moved to the recording and reproducing system 114 with the cartridge holding means 110 holding the cartridge 113. Then the cartridge 113 is loaded in the system 114. After the cartridge 113 is subjected to a predetermined process in the recording and reproducing system 114, the cartridge holding means 110 again grasps the cartridge 113 and the movable member 111 moves to the cartridge discharge position, which may be constituted as a discharge conveyor 115, carrying the cartridge 113. The movable member 111 is moved among the cartridge supply position, the recording and reproducing system and the cartridge discharge position (up and down as seen in FIG. 3) by a ball screw 116 rotated in forward and reverse directions by an electric motor 118, and the cartridge holding means 110 is moved rightward and leftward by an air cylinder 117. That is, the holding means 110 is moved leftward to grasp the cartridge 113 on the supply conveyor 112, and then moved rightward, and thereafter, the movable member 111 is moved to a position opposing to the recording and reproducing system 114. Subsequently, the holding means 110 is moved leftward with the cartridge 113 and causes the cartridge 113 to be loaded in the recording and reproducing system 114. After the cartridge 113 is subjected to the predetermined process, the holding means grasps the cartridge 113 and is returned to the rightward position, thereby taking out the cartridge 113 from the system 114, and then the movable member 111 is moved to the discharge conveyor 115 to place the cartridge 113 thereon.
However with the automatic cartridge loading-and-unloading device described above, it is difficult to sufficiently improve the working efficiency of the recording and reproducing system. That is, assuming that, for the purpose of simplification, the distance between the supply conveyor 112 and the recording and reproducing system 114 is equal to the distance between the recording and reproducing system 114 and the discharge conveyor 115, the distance being represented by a, and the stroke of the holding means 110 is represented by b, the moving distance L of the holding means 110 over which the holding means 110 must be moved to unload the magnetic disk cartridge 113 from the system 114, to transfer the cartridge 113 to the discharge conveyor 115 and to load the next cartridge 113 in the system 114 is as represented by the following formula. EQU L=b+a+2b+2a+2b+a+b=4a+6b
Assuming that a=15 cm, b=20 cm, and the speed of lateral movement of the holding means 110 and the speed of vertical movement of the holding means 110 (that is, the speed of movement of the movable member 111) are both 10 cm/sec, the moving distance L is 180 cm and the time required for the holding means 110 to travel over the distance L is 18 seconds. Further, when it is assumed that the time required for the predetermined process in the system 114 is 60 seconds in this case, the working efficiency of the system 114 is only 77% [=60/(60+18)].
The working efficiency may be improved by shortening the distance between the supply conveyor 112 and the discharge conveyor 115. However, even if the discharge conveyor 115 is disposed between the supply conveyor 112 and the recording and reproducing system 114 spaced from each other by the distance a as shown in FIG. 4, the distance L is shortened only by 2a, that is, L=2a+6b, and the working efficiency is merely improved to 80%.
Further, though the working efficiency may be improved by providing a plurality of loading-and-unloading devices so that as soon as one loading-and-unloading device unloads a magnetic disk cartridge from the recording and reproducing system, another loading-and-unloading device loads another cartridge in the system, this substantially adds to the equipment cost.